New Jerseyans, more than most around the country, have a lot at stake in the current debate over the tax benefits homeowners get from their mortgage.

Nearly one out of every three Garden State tax filers deducted the interest they paid on their mortgage from their 2010 federal tax bill, according to a new study by the Pew Charitable Trusts. That’s well above the national average of 26 percent for the year.

And it translates into a lot of money people don’t have to pay the federal government.

For all New Jersey tax filers — including those who did not claim mortgage interest — the average federal deduction was $3,667 for 2010, the Pew study found, using the most recent state-level data available.

But for those Garden Staters who claimed the mortgage interest they paid, the average deduction rose to $11,411.

Of course, the difference between the two figures can’t be attributed to mortgage interest alone. And the deduction does not translate to a dollar-for-dollar savings from one’s tax bill.

But it still amounts to a huge slice of tax revenue the federal government doesn’t get.

Tax expenditures

For 2011, the $360 billion in deductions that taxpayers claimed cost the U.S. Treasury $72 billion in revenue, Pew researchers wrote. In 2012, the lost revenue shrank slightly to $68 billion.

That dollar amount puts the interest deduction among the highest "tax expenditures" for the federal government. As a result, the benefit once again is being eyed by those looking to overhaul the tax code and wrangle down the federal deficit.

The House Ways and Means Committee in late April convened a hearing on residential tax breaks, at which its chairman Dave Camp (R-Mich.) called for a "careful, thoughtful review" of them.

President Obama’s budget proposal seeks to limit the credit that upper-income earners get for the mortgage interest they pay.

The Pew study does not take a stance on whether the mortgage interest deduction should be modified. But its authors say their data, which also dive into how individual U.S. ZIP codes claimed the deduction in 2007, shows the complexity that would accompany any reform. That’s because different sections of the country, and even different sections of states themselves, claim the deduction at widely different rates. While one area might not feel the affect of a change, another could see a big impact to its local economy.

"How you structure the change really matters," Anne Stauffer, project director for Pew, said in an interview. She added that the group plans to follow up the study by looking how changes could impact state tax revenue.

A nuanced view

In general, the mortgage interest deduction is claimed most often in the Northeast and in the West. But a higher percentage of Utah dwellers, 33 percent, took the deduction than New York state (23 percent), Pew found, looking at the 2010 data. Maryland had the highest rate, at nearly 37 percent, while West Virginia had the lowest, at 15 percent. New Jersey’s rate was 32 percent.

It is not clear why there is such variation in the claim rates, although demographics, wealth and the proportion of renters likely plays into the equation, Pew officials said. Less wealthy households may be less likely to claim mortgage interest because, in order to do so, they have to itemize their deductions, rather than take the standard deduction.

The zip code-level data that Pew studied shows an even more nuanced view. (Pew had to rely on the 2007 data because it is the only zip code-level information about the mortgage deduction that the Internal Revenue Service has released.)

Some of the largest metropolitan areas, including a stretch between Wayne and White Plains, N.Y., had below-average claim rates, while areas like Boulder, Colo., and Bend Ore., take the deduction more often than the average.

In New Jersey, the area of Camden, Gloucester and Burlington counties had the highest percentage of tax filers who took the mortgage interest deduction in 2007: 36.6 percent.

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But within that ranking were some of the highest and lowest claim rates among New Jersey’s mortgage deduction claim rates. At 55 percent, the Mount Royal section of East Greenwich Township, Gloucester County, had the highest claim rate of all New Jersey zip codes, with its neighboring section, Mickleton, trailing not far behind, at 52 percent. Both hamlets have undergone a rapid transformation in recent years from farming to bedroom communities.

At the other end of the spectrum, zip codes for the city of Camden had some of the state’s lowest claim rates: from 3 to 7 percent. Zip codes for Trenton, Newark and Paterson also filled out the bottom ranks of those who claimed the mortgage interest deduction.

The area with the largest number of claimants were in Monmouth, Ocean, Somerset and Middlesex counties: about 419,000 of the area’s 1.17 million tax filers sought the deduction.

'Like dope'

What all of this will mean in Washington remains to be seen. Efforts to modify the tax break are backed by some housing scholars, who question whether they really encourage home ownership. Alan Mallach, a senior fellow with Brookings Institution and former director of Trenton’s Department of Housing & Development, said research has shown that the deduction inspires people to buy more expensive homes than they otherwise would. This in turn helps drive up the price of housing, he said.

"It’s pretty much all around a bad thing," Mallach said in an interview. "But it’s like dope: we’ve gotten addicted to it."

Any effort to curb the deduction, however, faces stiff resistance. The National Association of Realtors and others involved in the housing industry have campaigned to defend the benefit, warning that changes could harm the nation’s gradual housing recovery.

INTERACTIVE MAP

The interactive map below shows the rate at which New Jersey tax payers claimed the mortgage interest deduction on their 2007 federal tax return. The data, provided by the Pew Charitable Trusts, is broken down by zip code. Area that appear transparent are zip codes or areas for which Pew did not have data.

• Claim rate shows the percent of tax filers in the zip code who claimed the mortgage interest deduction.

• Average deduction per tax filer shows the average dollar amount that all tax filers in the zip code claimed on their tax return, including those who did not claim mortgage interest.

• Average deduction per claimant shows the average deduction only for those who claimed the mortgage interest deduction.

To view data for the entire U.S., visit the project on the Pew website here.